<?php

if (!defined('BASEPATH'))
  exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */
// ------------------------------------------------------------------------

/**
 * File Uploading Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Uploads
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/file_uploading.html
 */
class CI_Upload {

  public $max_size = 0;
  public $max_width = 0;
  public $max_height = 0;
  public $max_filename = 0;
  public $allowed_types = "";
  public $file_temp = "";
  public $file_name = "";
  public $orig_name = "";
  public $file_type = "";
  public $file_size = "";
  public $file_ext = "";
  public $upload_path = "";
  public $overwrite = FALSE;
  public $encrypt_name = FALSE;
  public $is_image = FALSE;
  public $image_width = '';
  public $image_height = '';
  public $image_type = '';
  public $image_size_str = '';
  public $error_msg = array();
  public $mimes = array();
  public $remove_spaces = TRUE;
  public $xss_clean = FALSE;
  public $temp_prefix = "temp_file_";
  public $client_name = '';
  protected $_file_name_override = '';

  /**
   * Constructor
   *
   * @access	public
   */
  public function __construct($props = array()) {
    if (count($props) > 0) {
      $this->initialize($props);
    }

    log_message('debug', "Upload Class Initialized");
  }

  // --------------------------------------------------------------------

  /**
   * Initialize preferences
   *
   * @param	array
   * @return	void
   */
  public function initialize($config = array()) {
    $defaults = array(
        'max_size' => 0,
        'max_width' => 0,
        'max_height' => 0,
        'max_filename' => 0,
        'allowed_types' => "",
        'file_temp' => "",
        'file_name' => "",
        'orig_name' => "",
        'file_type' => "",
        'file_size' => "",
        'file_ext' => "",
        'upload_path' => "",
        'overwrite' => FALSE,
        'encrypt_name' => FALSE,
        'is_image' => FALSE,
        'image_width' => '',
        'image_height' => '',
        'image_type' => '',
        'image_size_str' => '',
        'error_msg' => array(),
        'mimes' => array(),
        'remove_spaces' => TRUE,
        'xss_clean' => FALSE,
        'temp_prefix' => "temp_file_",
        'client_name' => ''
    );


    foreach ($defaults as $key => $val) {
      if (isset($config[$key])) {
        $method = 'set_' . $key;
        if (method_exists($this, $method)) {
          $this->$method($config[$key]);
        } else {
          $this->$key = $config[$key];
        }
      } else {
        $this->$key = $val;
      }
    }

    // if a file_name was provided in the config, use it instead of the user input
    // supplied file name for all uploads until initialized again
    $this->_file_name_override = $this->file_name;
  }

  // --------------------------------------------------------------------

  /**
   * Perform the file upload
   *
   * @return	bool
   */
  public function do_upload($field = 'userfile') {

    // Is $_FILES[$field] set? If not, no reason to continue.
    if (!isset($_FILES[$field])) {
      $this->set_error('upload_no_file_selected');
      return FALSE;
    }

    // Is the upload path valid?
    if (!$this->validate_upload_path()) {
      // errors will already be set by validate_upload_path() so just return FALSE
      return FALSE;
    }

    // Was the file able to be uploaded? If not, determine the reason why.
    if (!is_uploaded_file($_FILES[$field]['tmp_name'])) {
      $error = (!isset($_FILES[$field]['error'])) ? 4 : $_FILES[$field]['error'];

      switch ($error) {
        case 1: // UPLOAD_ERR_INI_SIZE
          $this->set_error('upload_file_exceeds_limit');
          break;
        case 2: // UPLOAD_ERR_FORM_SIZE
          $this->set_error('upload_file_exceeds_form_limit');
          break;
        case 3: // UPLOAD_ERR_PARTIAL
          $this->set_error('upload_file_partial');
          break;
        case 4: // UPLOAD_ERR_NO_FILE
          $this->set_error('upload_no_file_selected');
          break;
        case 6: // UPLOAD_ERR_NO_TMP_DIR
          $this->set_error('upload_no_temp_directory');
          break;
        case 7: // UPLOAD_ERR_CANT_WRITE
          $this->set_error('upload_unable_to_write_file');
          break;
        case 8: // UPLOAD_ERR_EXTENSION
          $this->set_error('upload_stopped_by_extension');
          break;
        default : $this->set_error('upload_no_file_selected');
          break;
      }

      return FALSE;
    }


    // Set the uploaded data as class variables
    $this->file_temp = $_FILES[$field]['tmp_name'];
    $this->file_size = $_FILES[$field]['size'];
    $this->_file_mime_type($_FILES[$field]);
    $this->file_type = preg_replace("/^(.+?);.*$/", "\\1", $this->file_type);
    $this->file_type = strtolower(trim(stripslashes($this->file_type), '"'));
    $this->file_name = $this->_prep_filename($_FILES[$field]['name']);
    $this->file_ext = $this->get_extension($this->file_name);
    $this->client_name = $this->file_name;

    // Is the file type allowed to be uploaded?
    if (!$this->is_allowed_filetype()) {
      $this->set_error('upload_invalid_filetype');
      return FALSE;
    }

    // if we're overriding, let's now make sure the new name and type is allowed
    if ($this->_file_name_override != '') {
      $this->file_name = $this->_prep_filename($this->_file_name_override);

      // If no extension was provided in the file_name config item, use the uploaded one
      if (strpos($this->_file_name_override, '.') === FALSE) {
        $this->file_name .= $this->file_ext;
      }

      // An extension was provided, lets have it!
      else {
        $this->file_ext = $this->get_extension($this->_file_name_override);
      }

      if (!$this->is_allowed_filetype(TRUE)) {
        $this->set_error('upload_invalid_filetype');
        return FALSE;
      }
    }

    // Convert the file size to kilobytes
    if ($this->file_size > 0) {
      $this->file_size = round($this->file_size / 1024, 2);
    }

    // Is the file size within the allowed maximum?
    if (!$this->is_allowed_filesize()) {
      $this->set_error('upload_invalid_filesize');
      return FALSE;
    }

    // Are the image dimensions within the allowed size?
    // Note: This can fail if the server has an open_basdir restriction.
    if (!$this->is_allowed_dimensions()) {
      $this->set_error('upload_invalid_dimensions');
      return FALSE;
    }

    // Sanitize the file name for security
    $this->file_name = $this->clean_file_name($this->file_name);

    // Truncate the file name if it's too long
    if ($this->max_filename > 0) {
      $this->file_name = $this->limit_filename_length($this->file_name, $this->max_filename);
    }

    // Remove white spaces in the name
    if ($this->remove_spaces == TRUE) {
      $this->file_name = preg_replace("/\s+/", "_", $this->file_name);
    }

    /*
     * Validate the file name
     * This function appends an number onto the end of
     * the file if one with the same name already exists.
     * If it returns false there was a problem.
     */
    $this->orig_name = $this->file_name;

    if ($this->overwrite == FALSE) {
      $this->file_name = $this->set_filename($this->upload_path, $this->file_name);

      if ($this->file_name === FALSE) {
        return FALSE;
      }
    }

    /*
     * Run the file through the XSS hacking filter
     * This helps prevent malicious code from being
     * embedded within a file.  Scripts can easily
     * be disguised as images or other file types.
     */
    if ($this->xss_clean) {
      if ($this->do_xss_clean() === FALSE) {
        $this->set_error('upload_unable_to_write_file');
        return FALSE;
      }
    }

    /*
     * Move the file to the final destination
     * To deal with different server configurations
     * we'll attempt to use copy() first.  If that fails
     * we'll use move_uploaded_file().  One of the two should
     * reliably work in most environments
     */
    if (!@copy($this->file_temp, $this->upload_path . $this->file_name)) {
      if (!@move_uploaded_file($this->file_temp, $this->upload_path . $this->file_name)) {
        $this->set_error('upload_destination_error');
        return FALSE;
      }
    }

    /*
     * Set the finalized image dimensions
     * This sets the image width/height (assuming the
     * file was an image).  We use this information
     * in the "data" function.
     */
    $this->set_image_properties($this->upload_path . $this->file_name);

    return TRUE;
  }

  // --------------------------------------------------------------------

  /**
   * Finalized Data Array
   *
   * Returns an associative array containing all of the information
   * related to the upload, allowing the developer easy access in one array.
   *
   * @return	array
   */
  public function data() {
    return array(
        'file_name' => $this->file_name,
        'file_type' => $this->file_type,
        'file_path' => $this->upload_path,
        'full_path' => $this->upload_path . $this->file_name,
        'raw_name' => str_replace($this->file_ext, '', $this->file_name),
        'orig_name' => $this->orig_name,
        'client_name' => $this->client_name,
        'file_ext' => $this->file_ext,
        'file_size' => $this->file_size,
        'is_image' => $this->is_image(),
        'image_width' => $this->image_width,
        'image_height' => $this->image_height,
        'image_type' => $this->image_type,
        'image_size_str' => $this->image_size_str,
    );
  }

  // --------------------------------------------------------------------

  /**
   * Set Upload Path
   *
   * @param	string
   * @return	void
   */
  public function set_upload_path($path) {
    // Make sure it has a trailing slash
    $this->upload_path = rtrim($path, '/') . '/';
  }

  // --------------------------------------------------------------------

  /**
   * Set the file name
   *
   * This function takes a filename/path as input and looks for the
   * existence of a file with the same name. If found, it will append a
   * number to the end of the filename to avoid overwriting a pre-existing file.
   *
   * @param	string
   * @param	string
   * @return	string
   */
  public function set_filename($path, $filename) {
    if ($this->encrypt_name == TRUE) {
      mt_srand();
      $filename = md5(uniqid(mt_rand())) . $this->file_ext;
    }

    if (!file_exists($path . $filename)) {
      return $filename;
    }

    $filename = str_replace($this->file_ext, '', $filename);

    $new_filename = '';
    for ($i = 1; $i < 100; $i++) {
      if (!file_exists($path . $filename . $i . $this->file_ext)) {
        $new_filename = $filename . $i . $this->file_ext;
        break;
      }
    }

    if ($new_filename == '') {
      $this->set_error('upload_bad_filename');
      return FALSE;
    } else {
      return $new_filename;
    }
  }

  // --------------------------------------------------------------------

  /**
   * Set Maximum File Size
   *
   * @param	integer
   * @return	void
   */
  public function set_max_filesize($n) {
    $this->max_size = ((int) $n < 0) ? 0 : (int) $n;
  }

  // --------------------------------------------------------------------

  /**
   * Set Maximum File Name Length
   *
   * @param	integer
   * @return	void
   */
  public function set_max_filename($n) {
    $this->max_filename = ((int) $n < 0) ? 0 : (int) $n;
  }

  // --------------------------------------------------------------------

  /**
   * Set Maximum Image Width
   *
   * @param	integer
   * @return	void
   */
  public function set_max_width($n) {
    $this->max_width = ((int) $n < 0) ? 0 : (int) $n;
  }

  // --------------------------------------------------------------------

  /**
   * Set Maximum Image Height
   *
   * @param	integer
   * @return	void
   */
  public function set_max_height($n) {
    $this->max_height = ((int) $n < 0) ? 0 : (int) $n;
  }

  // --------------------------------------------------------------------

  /**
   * Set Allowed File Types
   *
   * @param	string
   * @return	void
   */
  public function set_allowed_types($types) {
    if (!is_array($types) && $types == '*') {
      $this->allowed_types = '*';
      return;
    }
    $this->allowed_types = explode('|', $types);
  }

  // --------------------------------------------------------------------

  /**
   * Set Image Properties
   *
   * Uses GD to determine the width/height/type of image
   *
   * @param	string
   * @return	void
   */
  public function set_image_properties($path = '') {
    if (!$this->is_image()) {
      return;
    }

    if (function_exists('getimagesize')) {
      if (FALSE !== ($D = @getimagesize($path))) {
        $types = array(1 => 'gif', 2 => 'jpeg', 3 => 'png');

        $this->image_width = $D['0'];
        $this->image_height = $D['1'];
        $this->image_type = (!isset($types[$D['2']])) ? 'unknown' : $types[$D['2']];
        $this->image_size_str = $D['3'];  // string containing height and width
      }
    }
  }

  // --------------------------------------------------------------------

  /**
   * Set XSS Clean
   *
   * Enables the XSS flag so that the file that was uploaded
   * will be run through the XSS filter.
   *
   * @param	bool
   * @return	void
   */
  public function set_xss_clean($flag = FALSE) {
    $this->xss_clean = ($flag == TRUE) ? TRUE : FALSE;
  }

  // --------------------------------------------------------------------

  /**
   * Validate the image
   *
   * @return	bool
   */
  public function is_image() {
    // IE will sometimes return odd mime-types during upload, so here we just standardize all
    // jpegs or pngs to the same file type.

    $png_mimes = array('image/x-png');
    $jpeg_mimes = array('image/jpg', 'image/jpe', 'image/jpeg', 'image/pjpeg');

    if (in_array($this->file_type, $png_mimes)) {
      $this->file_type = 'image/png';
    }

    if (in_array($this->file_type, $jpeg_mimes)) {
      $this->file_type = 'image/jpeg';
    }

    $img_mimes = array(
        'image/gif',
        'image/jpeg',
        'image/png',
    );

    return (in_array($this->file_type, $img_mimes, TRUE)) ? TRUE : FALSE;
  }

  // --------------------------------------------------------------------

  /**
   * Verify that the filetype is allowed
   *
   * @return	bool
   */
  public function is_allowed_filetype($ignore_mime = FALSE) {
    if ($this->allowed_types == '*') {
      return TRUE;
    }

    if (count($this->allowed_types) == 0 OR !is_array($this->allowed_types)) {
      $this->set_error('upload_no_file_types');
      return FALSE;
    }

    $ext = strtolower(ltrim($this->file_ext, '.'));

    if (!in_array($ext, $this->allowed_types)) {
      return FALSE;
    }

    // Images get some additional checks
    $image_types = array('gif', 'jpg', 'jpeg', 'png', 'jpe');

    if (in_array($ext, $image_types)) {
      if (getimagesize($this->file_temp) === FALSE) {
        return FALSE;
      }
    }

    if ($ignore_mime === TRUE) {
      return TRUE;
    }

    $mime = $this->mimes_types($ext);

    if (is_array($mime)) {
      if (in_array($this->file_type, $mime, TRUE)) {
        return TRUE;
      }
    } elseif ($mime == $this->file_type) {
      return TRUE;
    }

    return FALSE;
  }

  // --------------------------------------------------------------------

  /**
   * Verify that the file is within the allowed size
   *
   * @return	bool
   */
  public function is_allowed_filesize() {
    if ($this->max_size != 0 AND $this->file_size > $this->max_size) {
      return FALSE;
    } else {
      return TRUE;
    }
  }

  // --------------------------------------------------------------------

  /**
   * Verify that the image is within the allowed width/height
   *
   * @return	bool
   */
  public function is_allowed_dimensions() {
    if (!$this->is_image()) {
      return TRUE;
    }

    if (function_exists('getimagesize')) {
      $D = @getimagesize($this->file_temp);

      if ($this->max_width > 0 AND $D['0'] > $this->max_width) {
        return FALSE;
      }

      if ($this->max_height > 0 AND $D['1'] > $this->max_height) {
        return FALSE;
      }

      return TRUE;
    }

    return TRUE;
  }

  // --------------------------------------------------------------------

  /**
   * Validate Upload Path
   *
   * Verifies that it is a valid upload path with proper permissions.
   *
   *
   * @return	bool
   */
  public function validate_upload_path() {
    if ($this->upload_path == '') {
      $this->set_error('upload_no_filepath');
      return FALSE;
    }

    if (function_exists('realpath') AND @realpath($this->upload_path) !== FALSE) {
      $this->upload_path = str_replace("\\", "/", realpath($this->upload_path));
    }

    if (!@is_dir($this->upload_path)) {
      $this->set_error('upload_no_filepath');
      return FALSE;
    }

    if (!is_really_writable($this->upload_path)) {
      $this->set_error('upload_not_writable');
      return FALSE;
    }

    $this->upload_path = preg_replace("/(.+?)\/*$/", "\\1/", $this->upload_path);
    return TRUE;
  }

  // --------------------------------------------------------------------

  /**
   * Extract the file extension
   *
   * @param	string
   * @return	string
   */
  public function get_extension($filename) {
    $x = explode('.', $filename);
    return '.' . end($x);
  }

  // --------------------------------------------------------------------

  /**
   * Clean the file name for security
   *
   * @param	string
   * @return	string
   */
  public function clean_file_name($filename) {
    $bad = array(
        "<!--",
        "-->",
        "'",
        "<",
        ">",
        '"',
        '&',
        '$',
        '=',
        ';',
        '?',
        '/',
        "%20",
        "%22",
        "%3c", // <
        "%253c", // <
        "%3e", // >
        "%0e", // >
        "%28", // (
        "%29", // )
        "%2528", // (
        "%26", // &
        "%24", // $
        "%3f", // ?
        "%3b", // ;
        "%3d"  // =
    );

    $filename = str_replace($bad, '', $filename);

    return stripslashes($filename);
  }

  // --------------------------------------------------------------------

  /**
   * Limit the File Name Length
   *
   * @param	string
   * @return	string
   */
  public function limit_filename_length($filename, $length) {
    if (strlen($filename) < $length) {
      return $filename;
    }

    $ext = '';
    if (strpos($filename, '.') !== FALSE) {
      $parts = explode('.', $filename);
      $ext = '.' . array_pop($parts);
      $filename = implode('.', $parts);
    }

    return substr($filename, 0, ($length - strlen($ext))) . $ext;
  }

  // --------------------------------------------------------------------

  /**
   * Runs the file through the XSS clean function
   *
   * This prevents people from embedding malicious code in their files.
   * I'm not sure that it won't negatively affect certain files in unexpected ways,
   * but so far I haven't found that it causes trouble.
   *
   * @return	void
   */
  public function do_xss_clean() {
    $file = $this->file_temp;

    if (filesize($file) == 0) {
      return FALSE;
    }

    if (function_exists('memory_get_usage') && memory_get_usage() && ini_get('memory_limit') != '') {
      $current = ini_get('memory_limit') * 1024 * 1024;

      // There was a bug/behavioural change in PHP 5.2, where numbers over one million get output
      // into scientific notation.  number_format() ensures this number is an integer
      // http://bugs.php.net/bug.php?id=43053

      $new_memory = number_format(ceil(filesize($file) + $current), 0, '.', '');

      ini_set('memory_limit', $new_memory); // When an integer is used, the value is measured in bytes. - PHP.net
    }

    // If the file being uploaded is an image, then we should have no problem with XSS attacks (in theory), but
    // IE can be fooled into mime-type detecting a malformed image as an html file, thus executing an XSS attack on anyone
    // using IE who looks at the image.  It does this by inspecting the first 255 bytes of an image.  To get around this
    // CI will itself look at the first 255 bytes of an image to determine its relative safety.  This can save a lot of
    // processor power and time if it is actually a clean image, as it will be in nearly all instances _except_ an
    // attempted XSS attack.

    if (function_exists('getimagesize') && @getimagesize($file) !== FALSE) {
      if (($file = @fopen($file, 'rb')) === FALSE) { // "b" to force binary
        return FALSE; // Couldn't open the file, return FALSE
      }

      $opening_bytes = fread($file, 256);
      fclose($file);

      // These are known to throw IE into mime-type detection chaos
      // <a, <body, <head, <html, <img, <plaintext, <pre, <script, <table, <title
      // title is basically just in SVG, but we filter it anyhow

      if (!preg_match('/<(a|body|head|html|img|plaintext|pre|script|table|title)[\s>]/i', $opening_bytes)) {
        return TRUE; // its an image, no "triggers" detected in the first 256 bytes, we're good
      } else {
        return FALSE;
      }
    }

    if (($data = @file_get_contents($file)) === FALSE) {
      return FALSE;
    }

    $CI = & get_instance();
    return $CI->security->xss_clean($data, TRUE);
  }

  // --------------------------------------------------------------------

  /**
   * Set an error message
   *
   * @param	string
   * @return	void
   */
  public function set_error($msg) {
    $CI = & get_instance();
    $CI->lang->load('upload');

    if (is_array($msg)) {
      foreach ($msg as $val) {
        $msg = ($CI->lang->line($val) == FALSE) ? $val : $CI->lang->line($val);
        $this->error_msg[] = $msg;
        log_message('error', $msg);
      }
    } else {
      $msg = ($CI->lang->line($msg) == FALSE) ? $msg : $CI->lang->line($msg);
      $this->error_msg[] = $msg;
      log_message('error', $msg);
    }
  }

  // --------------------------------------------------------------------

  /**
   * Display the error message
   *
   * @param	string
   * @param	string
   * @return	string
   */
  public function display_errors($open = '<p>', $close = '</p>') {
    $str = '';
    foreach ($this->error_msg as $val) {
      $str .= $open . $val . $close;
    }

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * List of Mime Types
   *
   * This is a list of mime types.  We use it to validate
   * the "allowed types" set by the developer
   *
   * @param	string
   * @return	string
   */
  public function mimes_types($mime) {
    global $mimes;

    if (count($this->mimes) == 0) {
      if (defined('ENVIRONMENT') AND is_file(APPPATH . 'config/' . ENVIRONMENT . '/mimes.php')) {
        include(APPPATH . 'config/' . ENVIRONMENT . '/mimes.php');
      } elseif (is_file(APPPATH . 'config/mimes.php')) {
        include(APPPATH . 'config//mimes.php');
      } else {
        return FALSE;
      }

      $this->mimes = $mimes;
      unset($mimes);
    }

    return (!isset($this->mimes[$mime])) ? FALSE : $this->mimes[$mime];
  }

  // --------------------------------------------------------------------

  /**
   * Prep Filename
   *
   * Prevents possible script execution from Apache's handling of files multiple extensions
   * http://httpd.apache.org/docs/1.3/mod/mod_mime.html#multipleext
   *
   * @param	string
   * @return	string
   */
  protected function _prep_filename($filename) {
    if (strpos($filename, '.') === FALSE OR $this->allowed_types == '*') {
      return $filename;
    }

    $parts = explode('.', $filename);
    $ext = array_pop($parts);
    $filename = array_shift($parts);

    foreach ($parts as $part) {
      if (!in_array(strtolower($part), $this->allowed_types) OR $this->mimes_types(strtolower($part)) === FALSE) {
        $filename .= '.' . $part . '_';
      } else {
        $filename .= '.' . $part;
      }
    }

    $filename .= '.' . $ext;

    return $filename;
  }

  // --------------------------------------------------------------------

  /**
   * File MIME type
   *
   * Detects the (actual) MIME type of the uploaded file, if possible.
   * The input array is expected to be $_FILES[$field]
   *
   * @param	array
   * @return	void
   */
  protected function _file_mime_type($file) {
    // We'll need this to validate the MIME info string (e.g. text/plain; charset=us-ascii)
    $regexp = '/^([a-z\-]+\/[a-z0-9\-\.\+]+)(;\s.+)?$/';

    /* Fileinfo extension - most reliable method
     *
     * Unfortunately, prior to PHP 5.3 - it's only available as a PECL extension and the
     * more convenient FILEINFO_MIME_TYPE flag doesn't exist.
     */
    if (function_exists('finfo_file')) {
      $finfo = finfo_open(FILEINFO_MIME);
      if (is_resource($finfo)) { // It is possible that a FALSE value is returned, if there is no magic MIME database file found on the system
        $mime = @finfo_file($finfo, $file['tmp_name']);
        finfo_close($finfo);

        /* According to the comments section of the PHP manual page,
         * it is possible that this function returns an empty string
         * for some files (e.g. if they don't exist in the magic MIME database)
         */
        if (is_string($mime) && preg_match($regexp, $mime, $matches)) {
          $this->file_type = $matches[1];
          return;
        }
      }
    }

    /* This is an ugly hack, but UNIX-type systems provide a "native" way to detect the file type,
     * which is still more secure than depending on the value of $_FILES[$field]['type'], and as it
     * was reported in issue #750 (https://github.com/EllisLab/CodeIgniter/issues/750) - it's better
     * than mime_content_type() as well, hence the attempts to try calling the command line with
     * three different functions.
     *
     * Notes:
     * 	- the DIRECTORY_SEPARATOR comparison ensures that we're not on a Windows system
     * 	- many system admins would disable the exec(), shell_exec(), popen() and similar functions
     * 	  due to security concerns, hence the function_exists() checks
     */
    if (DIRECTORY_SEPARATOR !== '\\') {
      $cmd = 'file --brief --mime ' . escapeshellarg($file['tmp_name']) . ' 2>&1';

      if (function_exists('exec')) {
        /* This might look confusing, as $mime is being populated with all of the output when set in the second parameter.
         * However, we only neeed the last line, which is the actual return value of exec(), and as such - it overwrites
         * anything that could already be set for $mime previously. This effectively makes the second parameter a dummy
         * value, which is only put to allow us to get the return status code.
         */
        $mime = @exec($cmd, $mime, $return_status);
        if ($return_status === 0 && is_string($mime) && preg_match($regexp, $mime, $matches)) {
          $this->file_type = $matches[1];
          return;
        }
      }

      if ((bool) @ini_get('safe_mode') === FALSE && function_exists('shell_exec')) {
        $mime = @shell_exec($cmd);
        if (strlen($mime) > 0) {
          $mime = explode("\n", trim($mime));
          if (preg_match($regexp, $mime[(count($mime) - 1)], $matches)) {
            $this->file_type = $matches[1];
            return;
          }
        }
      }

      if (function_exists('popen')) {
        $proc = @popen($cmd, 'r');
        if (is_resource($proc)) {
          $mime = @fread($proc, 512);
          @pclose($proc);
          if ($mime !== FALSE) {
            $mime = explode("\n", trim($mime));
            if (preg_match($regexp, $mime[(count($mime) - 1)], $matches)) {
              $this->file_type = $matches[1];
              return;
            }
          }
        }
      }
    }

    // Fall back to the deprecated mime_content_type(), if available (still better than $_FILES[$field]['type'])
    if (function_exists('mime_content_type')) {
      $this->file_type = @mime_content_type($file['tmp_name']);
      if (strlen($this->file_type) > 0) { // It's possible that mime_content_type() returns FALSE or an empty string
        return;
      }
    }

    $this->file_type = $file['type'];
  }

  // --------------------------------------------------------------------
}

// END Upload Class

/* End of file Upload.php */
/* Location: ./system/libraries/Upload.php */
